A detailed field test to study the operating characteristics of a water-loop heat pump system is being conducted in a commercial building in Stamford, CT. Details and interprets the results of the first year of the field test (November 1987 through October 1988), summarises the major findings, and describes the retrofit modifications for the second year and their initial results.

KEYWORDS: site testing, water heat pumps, heat pumps, commercial, buildings, modernising, USA, electric heating, offices, electric boilers, calculating, energy consumption, case studies.